Pairing the BM Pro Master Controller (the display) to the BM Pro Master Node (the I/Os) is discussed on page 18 of the BM Pro installation manual. This is available by registering at https://www.thormotorcoach.com/owner-resource/
with your VIN. Go to Manuals and download the BM Pro Installation manual.
I can't upload it here because it exceeds the allowable file size on this forum.
To Beau388's point about rebooting, just turn off the battery switch. That will kill all DC power, then turn it on about a minute later. Maybe that will work.